1: deadlifts with a olift clean type variation rather than a rip style DL
2: a high bar back squat would transfer better to Oly lifts.

Will my strength gains be slower if i use these variations of the lifts or should i stick with the SS /practical programming style of these lifts?

Yes, your absolute strength gains will be slower, particularly as measured by something like CFT or PL totals, but likely with other functional measures of strength as well. Your sports-specific strength will be higher as applied to olympic lifting. So if that's your aim, go that route.

If your aims are to get as strong and powerful as possible and you have no specific desires to compete in olympic lifting, go with SS, but make sure you do the cleans (and probably snatches as well).